216005 has 4 divisors (see below), whose sum is σ = 259212. Its totient is φ = 172800.

The previous prime is 215983. The next prime is 216023. The reversal of 216005 is 500612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 114244 + 101761 = 338^2 + 319^2 .

It is not a de Polignac number, because 216005 - 2¹⁴ = 199621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21596 + ... + 21605.

It is an arithmetic number, because the mean of its divisors is an integer number (64803).

216005 is a Friedman number, since it can be written as 60^(2+1+0)+5, using all its digits and the basic arithmetic operations.

2²¹⁶⁰⁰⁵ is an apocalyptic number.

It is an amenable number.

216005 is a deficient number, since it is larger than the sum of its proper divisors (43207).

216005 is an equidigital number, since it uses as much as digits as its factorization.

216005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43206.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 216005 is about 464.7633806573. The cubic root of 216005 is about 60.0004629594. Note that the first 3 decimals are identical.

Adding to 216005 its reverse (500612), we get a palindrome (716617).

The spelling of 216005 in words is "two hundred sixteen thousand, five".